The iFly program is on a SD card that needs to remain in the device to work. I would suggest you call iFly support and see what they say. Can you contact the old owner and find out if he's still got an active subscription, or the SD card with the program and map information on it.
I would imagine that most folks on here will say you should keep it, since many of us are using a 720 or 740.
Why?
The iFly is VERY daylight readable.
The yearly map subscrptions are reasonably priced.
The iFly team is quick to solve problems, and constantly upgrading the device.
One other item I really like is that it works with a remote control. Which means can keep the remote on a tether around my neck, and acknowledge alerts from "arar" instead of reaching over and trying to push a video button on the screen, perhaps several times.
Despite the "old" age, it can still run the latest software, can connect to most, if not all ADS-B IN devices as well.